1 files changed, 33 insertions, 0 deletions
diff --git a/browser/components/newtab/test/xpcshell/test_AboutHomeStartupCacheChild.js b/browser/components/newtab/test/xpcshell/test_AboutHomeStartupCacheChild.js
new file mode 100644
index 0000000000..a0cb2cf324
--- /dev/null
+++ b/browser/components/newtab/test/xpcshell/test_AboutHomeStartupCacheChild.js
@@ -0,0 +1,33 @@
+/* Any copyright is dedicated to the Public Domain.
+http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const { AboutHomeStartupCacheChild } = ChromeUtils.import(
+  "resource:///modules/AboutNewTabService.jsm"
+);
+
+/**
+ * Tests that AboutHomeStartupCacheChild will terminate its PromiseWorker
+ * on memory-pressure, and that a new PromiseWorker can then be generated on
+ * demand.
+ */
+add_task(async function test_memory_pressure() {
+  AboutHomeStartupCacheChild.init();
+
+  let worker = AboutHomeStartupCacheChild.getOrCreateWorker();
+  Assert.ok(worker, "Should have been able to get the worker.");
+
+  Assert.equal(
+    worker,
+    AboutHomeStartupCacheChild.getOrCreateWorker(),
+    "The worker is cached and re-usable."
+  );
+
+  Services.obs.notifyObservers(null, "memory-pressure", "heap-minimize");
+
+  let newWorker = AboutHomeStartupCacheChild.getOrCreateWorker();
+  Assert.notEqual(worker, newWorker, "Old worker should have been replaced.");
+
+  AboutHomeStartupCacheChild.uninit();
+});